1. Field of the Invention
The invention is directed to an improved magnet valve.
2. Description of the Prior Art
A conventional magnet valve, particularly for a hydraulic unit of the kind used for instance in an anti-lock brake system (ABS) or traction control system (TCS) or an electronic stability program system (ESP), is shown in FIG. 4. As FIG. 4 shows, the conventional magnet valve 40, which is open when without current, includes not only a magnet unit 5 with a cover plate 12 but also a valve cartridge, which includes a capsule 6, a valve insert 1, a tappet 20, a restoring spring 30, and an armature 7. In the production of the magnet valve 40, the capsule 6 and the valve insert 1 of the valve cartridge are joined together by pressing, and by means of a sealing weld 8, the valve cartridge is hydraulically sealed off from the atmosphere. In addition, the valve insert 1 absorbs the pressure forces that occur in the hydraulic system and conducts them via a calked flange 9 to a calked region, not shown, on a fluid block. The valve insert 1 moreover receives the so-called valve body 4, which includes a valve seat 10 into which the tappet 20 plunges in sealing fashion, in order to perform the sealing function of the magnet valve 40. As FIG. 4 also shows, the tappet 20 and the restoring spring 30 are guided in the valve insert 1; the tappet 20 is guided in a tappet guide 11; and the restoring spring 30 is guided radially on one end on the tappet 20 and rests in centered fashion on a contact face 21, while on the other end it rests, axially guided, on the valve body 4. FIG. 5 shows a conventional exemplary embodiment of the tappet 20. As can be seen from FIG. 5, the conventional tappet 20 includes the axial contact face 21; a spring guide 22 onto which the restoring spring 30 is slipped and guided inward radially in the short region of the spring guide 22; a tappet cone 23 is a transitional region between the spring guide 22; and a tappet dome 24, which plunges sealingly into the valve seat 10. No further fixation or centering of the restoring spring 30 at its installation site is provided for.